German Internet security experts Heise Security have discovered what it calls two "flaws" in Service Pack 2. Microsoft has said its Service Pack 2 offers users the latest security "innovations," but Internet security experts said hackers could exploit cracks in SP2 defences to exploit a user's computer.

According to Heise Security, "Computer hackers could evade SP2's new security features and infect a computer that uses Windows with a virus or a worm." Heise further explains that Windows also does not source information properly if files are overwritten so that it can "be tricked to execute files from the Internet" without sparking a warning, even if users install the new SP2 update.

A Microsoft spokesperson addressed the warning by saying, "Microsoft has investigated these reports and is not aware of any instance in which an attacker could specifically bypass the service in email or a Web browser to allow a malicious attacker access to a user's system. We continue to encourage customers to review and install Windows XP SP2."